In recent years, various investigations on techniques for reducing the amount of waste in processing of color photographic matrials have been made by necessity in order to reduce water pollution and to reduce processing costs. Such techniques are practically employed in certain processing steps. In particular, with respect to the color developing step, various kinds of methods have been hitherto proposed since a great burdon has been imposed to prevent environmental pollution caused by waste. For example, methods for regeneration of color developing solutions utilizing electrodialysis as described in Japanese Patent Application (OPI) Nos. 37731/79, 1048/81, 1049/81, 27142/81, 33644/81 and 149036/81 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") and Japanese Patent Publication No. 10199/86 are known. Further, various methods for regeneration of color developing solutions using active carbon as descried in Japanese Patent Publication No. 1571/80 and Japanese Patent Application (OPI) No. 14831/83, using an ion exchange membrane as described in Japanese Patent Application (OPI) No. 105820/77, or using an ion exchange resin as described in Japanese Patent Application (OPI) Nos. 144240/80, 146249/82 and 95352/86 are proposed.
However, these methods require a high level of control and a costly device in order to necessarily analize the color developing solution and regulate its composition. Consequently, these methods are practiced only in some large scale laboratories.
On the other hand, a processing method with low replenishment is also utilized wherein the amount of replenishment is reduced by regulating the composition of a replenisher for the color developing solution (hereinafter referred to as a color developing replenisher) without using the regeneration described above. In order to regulate the composition of a replenisher in a processing method with low replenishment, a means for concentration of consumed components, for example, a color developing agent and a preservative, etc. is employed for the purpose of supplying the necessary amount of the components even when the amount of replenisher is reduced. Further, when silver halide color photographic materials are treated, halogen ions are released in the color developing solution. In the processing method with low replenishment, the bromide ion concentration in particular increases in the color developing solution, and as a result, development is restrained. Therefore, in order to prevent the restraint of development, a means of reducing the bromide concentration in the replenisher as compared with conventional replenishment methods is generally employed.
The processing method with low replenishment described above is advantageous since it can be practiced without analysis of the composition of the solution in all particulars in the case of processing a certain large amount of photographic light-sensitive materials every day and of conducting the processing with a small range of reduction in the amount of replenisher.
However, when the amount of photographic light-sensitive materials to be processed (hereinafter simply referred to as a processing amount) is small or when the range of reduction in the amount of replenisher is large, the retention time of the solution in the processing tank is increased as a result of the reduction in the amount of replenisher. The long retention time causes changes in the composition of the developing solution due to evaporation of water and oxidation of the preservative and the developing agent and results in an undesirable severe change in processing performance.
The amount of replenisher for a color developing solution can be varied depending on the kind of photographic light-sensitive materials. For instance, in the case of a color negative film for photographing, the amount of replenisher is ordinarily about 1200 ml per m.sup.2 of the film. When the amount of replenisher is reduced to a range of 600 ml per m.sup.2 or less, the above described problem becomes notable. Compensation for the change may be possible to a certain degree if the processing amount is constant every day. However, it is well known in this field that the processing amount varies over a wide range depending on the day, month and season. Therefore, it is very difficult to maintain the desirable solution composition in the processing method with exceptionally low replenishment and the processing method results in a remarkable variation of gradation and fog density in the photographic material processed.
Accordingly, although the above described processing method with low replenishment is advantageous in view of simplicity, it can be practically employed only under a restricted processing condition. Further, the excessive reduction of the amount of replenisher cannot be actually effected.